Shock absorber for vehicles



July 7, 1936.

H. MORGENROTH SHOCK ABSORBER FOR VEHICLES Filed May 9, 1935 PatentedJuly 7, 1936 PATENT OFFICE 1 snoek ABsoRBEn. Foa VEHICLES Y HenriMorgenroth, Le Chesnay, France, assigner to: N. V. De Schelde,Amsterdam, Netherlands f Application May 9, 1935, Serial'No. 20,645V

In Germany October 3, 1933 2 claims. (c1. 267-8) My invention relates toshock absorbers for motor and other vehicles and more-especially toYthat type of devices'of this kind, which exert their braking action onthe vehicle frame only when .-5 the wheel axle is returning into itsposition of rest, i, e. during the upper half of its downward movementand the lower half of its upward movement. y

YThe typical means for operating such shock absorber is a cam acting ona piston arranged for reciprocation against the action of a Vspring in acylindrical casing lledV with oil or some other damping medium. In thenormal position of the vehicle spring this cam, in orderto be able 15,to act as described above, must assume its dead centre position, and thepiston will then move upwardly, during the upward andl downwardmovements of the wheel axle, without offering any resistance, the checkvalve opening to allow the damping liquid to pass through freely. Ontheother hand, when the axle returns into its position of rest, thepiston will move downwardly both during the ascending and descendingmovements of the axle, brakingV the movement of the 25 axle under theaction of a throttle valve preventing rapid passage of the liquid.

Apparently a shock absorber of this particular type should be far moreecient as regards the damping of oscillations than the normal absorb- 30ers which are operative throughout the upward and downward stroke of thepiston, since by cutting out the braking action during compression ofthe Vvehicle spring, when riding over a projection of the ground, orduring expansion of the 35 spring, when passing through a depression ofthe ground, the well known obnoxious increase of the first oscillationof the vehicle frame is avoided by the shock absorber. Nevertheless thetests conducted with shock absorbers of this 40 known type have notfurnished satisfactory results. This is due to the fact that the actionof these shock absorbers is the same during upward as well as duringdownward motion, since, as mentioned above, the piston, when damping the45 oscillations, moves downwardly in either case,

always actuating the same throttle valve. However, the damping effect ofa shock absorber should always be weaker in the upward than in thedownward direction, since with increasing 50 speed the axle, which, whenriding over a projection, is forced to give way upwardly, imparts to theshock absorber an ever increasing acceleration Vwhich finally equals arigid connection between the axle and the vehicle frame. On the other 55hand, when passing through a depression of the ground, the axle is notat all compelled to at once enter this depression, the wheel beinglifted., at higher speeds, off the ground, so that there results amaximum velocity of downward motion of the axle and consequently also anacceleration in downward direction, brought about by the shock absorber,which is never overstepped.

'I'hese considerations show clearly that in view of the frequentlyoccurring higher upward ve- 10 locity of the axle a shock absorber whichshall not damp oscillations more vigorously in upward than in downwarddirection, must be adjusted for much lesser action in this directionthan in the downward direction.

It has already been suggested to bring about a` different action of theshock absorber in one and the other direction by causing the cam or thepiston to actuate different throttle valves. Such devices are, however,unduly complicated and very sensitive against disturbances.

It has further been suggested to shape the cam .0r the piston surfacecooperating with it in such manner as to cause the upward stroke of thepiston to become shorter than its downward stroke.

Shock absorbers of the type aforesaid, however, involve the disadvantagethat the piston stroke will be comparatively short and moreover, on thecam returning to its dead centre position, since it acts on the pistonwith a transversal component, the piston may have the tendency ofjamming. Apart therefrom it may be desirable to obtain an action otherthan sinoidal. While this might be obtained by forming the piston withan uneven operating surface, the result would be unsatisfactory in viewof the high side pressure resulting therefrom.

In the drawing axed to this specification and forming part thereof twoforms of a shock absorber embodying my invention are illustrateddiagrammatically by way of example.

In the drawing Fig. 1 is an axial section of the first modificationshowing a cam of symmetrical configuration acting on a single-armedlever which in turn acts on the piston, while Fig. 2 is a similar viewof the second modication, in which a cam of asymmetrical form depressesa single-armed lever which in its turn acts on the piston.

Referring to the drawing, 20 is the vehicle frame, 2| the wheel axle, 22the cam shaft, 23 the lever arm xed to this shaft, 24 the linkconnecting this arm to the wheel axle and 25 the cam which in this caseis of the usual symmetrical form. 26 is the'piston mounted forreciprocation in the cylindrical portion of the casing 21 of the f rightinto its dead centre position, since it acts; on a part of the lever arm29 comparativelyr closeY to its pivot, the extent of the'angular''iiiiwen'lent/v of the lever arm 29 will Abe ,greaterthan ifthe cam returns to the dead centre position fromthe' left, When it actson a portion the leveidrnparatively remote from the pivot, i. ej'on 'alonger 'I lever arm. The two extreme positions oithe cam 25 are shown inthe drawing in lines ,l

and it will be seen that with the cam its right hand end position' thelever arinwill be. able to rise to a greater extentthan ifthe'camassumes its left hand' end position, Inthisfmodilcation of the` shockabsorber theV lever .29 always acts on the middleV portion vofr thepistonsurface, so that here allv injurious side 'pressure' is avoided.

The active surface ofthe lever arm29, whichis acted upon by the cam, isshown to be straight and plane` 1f itis desired to obtain a dampingcurve other than-'lsinoidaL this surface of the lever arm may be shapedaccordingly without any obnoxious side pressures bein'g exertedfon thepiston. Obviously here any desired variations maybe obtained by4replacing the symmetrical camby an asymmetrical one. Y

A detail of ay modification of the improved shockV absorber, inwhich anasymmetrical cam acts on the intermediate single-armed. lever, is shownby Way of example in Fig. 2, where 20 is the'vehiclefram-e, 2 I thewheel axle, 22?' the cam shaft, 23' the lever 'arm iixecl to thisshaft,` 24" thelink connecting this arm to the wheel axle and 2'5' thecam which .is of asymmetrical shape. 26" is the piston mounted forreciprocation inthe "Obviously in allcases the cams here Shown 2,046,527if?? i' cylindrical portion of the casing 21 of the shock absorber, 28being the coil spring tending to lift the piston.

29 is a single-armed lever xed to the journal 30', this lever arm 29'acting on the top surface 5' of the piston 26 with a rounded extension3l. The cam 25 acts on the lever 29' between its pivotrpoint and itsend, acting difierently when turned to either side ofY its dead centreposition. Consequently, the asymmetrical shape of the 10 cam 25' formsan easy means of predetermining, Yin combination with the shape anddimensions of thesinglearmed lever, the di'erence betweenthe upward anddownward strokes of the piston 262.-: f Y 15 might be. replaced byeccentrics carrying rollers. 'I wish 'it to be understood that I do notdesire to. be limited to the exact details oi' construction shown'anddescribed for 'obvious rmodifications will occur toa lperson V.skilledin theart rciaimsl.v A shockfabsorber comprising iin combination, adamping'. piston, a cam arranged to be oscillated by the actionof shocksand a'sing'le armed lever between said Vpiston andsaid carni, the endofv said'lever 'resting on lsaid piston-"the circumferential surface ofsaid cam contacting 'with'afpointi intermediate therend of the surfaceandthe pivot point 'of said lever.- 30

v2.2i shock absorber comprising -in combination,- a damping pistongacamarranged to be oscillated: by the action of shocks and a single-Yarmed lever between said-'piston "and said-cam,

theV end of said lever resting onsaid piston',Y the 35.`

circumferential surface of vsaidV cam" contacting with a pointintermediate the end of the vsurface and the pivot point of said leverinv a manner such that vthe distance betweenk said Contact point andsaid pivot. point vari-eswith varying 40 positions of said cam, one ofthe contacting surfaces being asymmetrically formed;

- `zV HNRrMoRGENRoTH.

